Machine for splitting or resawing insulating boards



Jan. 5, 1954 E. R. FERRARI 2,664,923

MACHINE FOR SPLITTING OR RESAWING INSULATING BOARDS Original Filed Nov.16, 1951 4 Sheets-Sheet 1 l|fiIil1r- -19 Da'lum Plane J "K Wark 197d I 1e 5 Y Pan i "J INVENTOR. .Er'n es? R.Ferr'a r1 Jan. 5, 1954 E. R.FERRARI 2,664,923

MACHINE FOR SPLITTING OR RESAWING INSULATING BOARDS Original Filed Nov.16, 1951 4 Sheets-Sheet 2 N m m r w m Is E LH IN VEN TOR.

Ern e sl' P. Ferrari Jan. 5, 1954 E. R. FERRARI 2,654,923

MACHINE FOR SPLITTING 0R RESAWING INSULATING BOARDS Original Filed Nov.16, 1951 4 Sheets-Sheet 3 IN VEN TOR.

frnesi'R.F rrari w L7H Patented Jan. 5, 1 954 MACHINE FOR SPLITTING ORRESAWING INSULATING BOARDS Ernest R. Ferrari, Vancouver, Wash., assignorto A. W. Schaupp and E. R. Ferrari, a copartnership, doing business asAmerican Smooth Saw 00., Klamath Falls, Oreg.

Original application November 16, 1951, Serial No.

Divided and this application October 14, 1952, Serial No. 314,663

3 Claims.

My invention relates to the splitting or resawing of insulated boardedgewise to provide cut pieces or sections which maybe used in theproduction of simulated split shakes and siding. To this end, the cutpieces or sections should be ta pered so as closely to resemble atapered wood shake or siding. It is difficult, if not impossible,economically, to form insulating board originally in tapered sections.Accordingly, many efforts have been made to resaw or to split the sheetsedgewiseon a taper to produce two complementary wedge-shaped pieces.These eiforts, however, have failed or proved impractical. Thedifficulty involved is that the sheets of insulating board are quitethin, spongy, soft, and fragile so a splitting or resawing operationcannot be per formed economically and efficiently by conventionalmethods or with conventional machinery. I use the word resaw herein toconnote sawing edgewise of a sheet, not flatwise or crosswise andwithout relation to the fact that the sheet is originally laid or formedwithout a sawing operation.

;- =Insul,ating board is formed from a web of matted fiber in a mannersimilar to the one by which paper is made. Because of the fact that theweb is made by flowing or otherwise applying a wetted sheet of materialto a perforate surface, it is difficult, if not impossible to lay such asheet with a varied thickness or a tapered section. Efforts made tosplit sheets of insulating board edgewise heretofore have beenunsuccessful because of the fibrous, spongy nature of the material andthe soft, fragile texture of the finished board. For example, a resaw ofusual construe I tion will tear and rip the fibers of the board and willproduce an uneven cut surface. Furthermore, to form a simulated shakefrom a board of standard size, it is necessary to sever the thin tionsare produced. Another and greater difficulty and hazard is thatconventional efforts to split edgewise or to resaw sheets of insulatingboard pull out small pieces of material which pile up and wedge aboutthe clearance space for the saw blade or other cutter which is formingthe split or kerf, and these pieces produce friction 2 and generate heatto such an extent that ignition of the highly flammable materialresults. Because of this fire danger, the resaw of an insulating boardhas become known in the industry as an ultra-hazardous undertaking.

I have discovered that sheets of softinsulating board may be splitedgewise by the use of a so-called smooth saw bandsaw if ordinaryresawing procedures are modified in several respects withregard to (1)guiding the sheets into the sawing area, (2) holding them to a fixedplane and pathway, (3) compressing'the sheets being rived by this sawingaction over the area where the sawing is being produced and rearwardlythereof, (4) flooding or wetting the sides of the saw blade with aliquid, such as a solvent, to prevent the binder in the insulating boardfrom accumulating on the blade, and (5) inclining the sheets obliquelyto the plane of the saw blade so the usual supports and operatingmechanism provided for the saw may be utilized.

My invention is embodied in a new machine which makes practical and safethe performance of such edgewise splitting or resawing of sheets ofinsulating material.

That material which generically is termed insulating board and withwhich my invention is concerned is produced from a variety of sourcematerials. These source materials, in the main, involve the utilizationof waste products, such, for example, as the stocks of sugar cane, cornstocks, flax shives, straw and wood chips. My experimental work has beendone in the main with insulating board made from wood chips of Douglasfir and a bitumen binder. One type of insulating board of this lattercharacter is sold under the trade nameof Firtex. However, this tradename material is but one exemplary type of insulating board and myinvention is intended for use with insulating board generally.

One common attribute of all insulating board is that it is soft andspongy and has little tensile strength as compared with hard board. someinsulating board is produced in sheets having relatively smooth, densesurfaces, from a fibrous mass having incorporated therein a resinous orbitumen binder. Some of these binders are quite flammable and mostinsulating boards exude the binder materials in the presence of heatsuch as is produced ina resawingaction. This exudation, then, is aproblem since it tends to form a hard deposit upon the saw blade and,after a short period, the deposit builds up to such an accumulation thatit renders the saw blade ineffective for producing a clean cut.Thereafter, either the blade must be removed or the machine must bestopped so the blade can be cleaned. I have discovered that theformation of these deposits and accumulations can be inhibited orprevented entirely by maintaining a wetted surface over the faces of thesaw blade as with a liquid solvent or cleaner applied in such volumethat it will .be taken up by the sawdust produced in the sawing action.This sawdust continuously will wipe :the solvent away and will carrywith it any accumulation of binder which is exuded from the sheet underthe heat produced by the resawing action.

My experiments in connection with this subject have established that theresawing or edgewise splitting of insulating board successfully may beproduced with a saw tooth .of the type disclosed in the United Statespatent to Ferrari and Hoffman, No. 2,071,618. In the sawing art, thistype of tooth is used to produce --s-mooth sawing. It differs from theordinary tooth in that the points are more narrow than the base and thesides diverge from the points toward the gullet. Further, the divergenttooth sides are maintained quite sharp so as to plane or shave the wallsof the saw kerf to a degree that boards thus sawed resemble planedboards rather than sawed boards.

I have discovered, however, that the use of the above described type ofsaw tooth alone or per se will not be satisfactory to resaw or to splitsheets of insulating board edgewise. The difficulty arises due to thefact that insulating board is quite spongy and it tends to yield underpressure so the divergent sides of the teeth cannot perform theirintended function as they do in lumber. This might be likened to the actof a man shaving his whiskers. The whiskers cannot be cut off sharplyand cleanly unless some substantial pressure be applied to the skineither by pulling the skin taut or by pressing the razor tightly againstthe skin. I have discovered that the same effect and result can beobtained in sawing by mounting two flat shoes closely adjacent thesawing area, which shoes are arranged to engage the opposite faces ofthe insulating board and to hold the board tightly against the saw.These shoes must be relieved somewhat over the area where the teeth routout the bottom of the kerf so the saw does not become pinched. They canexert substantial pressure, however, over the gullet of the saw bladeand this pressure causes the two halves of the split sheet to be bentinwardly and to rub against the gauge of the saw. Such a slight rub issufficient to hold the surfaces of the kerf against the saw blade and toproduce the shaving or planing action which is so important.

A second and equally important result is produced by the use of thesepressure shoes at the sawing area. Thus, the wedge-shaped sections orsimulated shakes which are to be produced must narrow to a thin edge,approximately oneeighth of an inch thick. The boards are resawed or aresplit on edge, however, and the cutter or saw blade moves toward the sawtable in passing through the cutting area. Thus, the board is supportedby only one thin edge, which edge bears against and rests upon the sawtable and lower guide while spanning the tooth clearance opening. It isthe fast moving ripping action of the moving saw blade which tends topull upon 4 this thin edge of the board and of the cut piecessufliciently to break chunks therefrom. However, in accord with myinvention, if the sides of the board and the cut pieces are held tightlyby the shoes and a substantial pressure is exerted thereby, the soleswill prevent the thin edges of the cut pieces from crumbling orrupturing. That is to say, the rubbing pressure of the shoes on the.thin out area tends to hold this critical thin edge integral andunbroken, even though the board and cut pieces have only an edge contactfor support. The upper edge of the board, on the other hand, does notrequire as much support since the saw is moving downwardly away from theupper edge. Thus, the entire body of the underlying board acts as asupport and rupturing does not occur so readily. That is, the materialitself has sufiicient strength to resist breakage along the upper edgeduring the sawing operation.

For the above reasons, it is one object of my invention to provide apair of spring pressed and parallel mounted shoes for a bandsaw machine,such shoes to be positioned on opposite sides of the saw blade wherethey will contact, hold, and press the cut pieces of board as these outpieces flow past the saw blade. In contrast to mere guides, these shoespress upon, compress, and support the cut pieces effectively tostrengthen the same at the critical areas.

Another object of my invention is to hold and press the cut piecestogether, with a preselected pressure, as these pieces move past thegullet line and the rear portion of the saw blade.

In conjunction with the smooth saw teeth above mentioned, my inventionemploys a tunnel which is complementary to the shape of the board whichis to be split. This tunnel is unique in that it is bounded by powerdriven elements which move the board toward the saw and by guides,fences, and idlers, which steer and guide both faces and both edges ofthe board with precision while it is moved. Additionally, the tunnel istilted with respect to the saw blade so the board will encounter theteeth at an angle rather than straight on and the cut pieces thereforeWill acquire the desired taper .or wedge-shaped appearance to simulateshakes or siding. Sequentially, my invention proceeds by moving aplurality of the boards through the tunnel and past the saw blade, oneafter another, in a steady stream; by abutting each board end to end asit is moved along; and by supporting and holding the cut pieces togetherwith a preselected pressure as they pass the saw blade. Commercially,this has proved practical and near perfect cuts can be made so long asthe insulating board is of the type which employs no binder. If,however, as is common with many insulating boards, a low melting pointbitumen or resin binder has been used in forming the board, experiencehas shown that this binder will present an additional problem. Thus,friction is developed as the splitting or resawing progresses, and thisfriction heats the saw blade to a temperature where the bitumen or resinbinder is exuded. As previously explained, a certain amount of thismaterial will accumulate upon the teeth and upon both faces of the sawblade. For example, if a band resaw blade is utilized, substantial heatis generated adjacent the work area of the blade, yet only a portion ofthis heat is dissipated adjacent the return area of the continuous sawblade. Accordingly, that binder which is exuded tends to harden and toaccumulate as the blade moves along and is cooledl Such an accumulationof binder can be fatal to'the successful practice of my invention.Further, experience has shown that constep wherein the saw bladecontinuously is flooded, wetted, and bathed with a liquid. This liquidmay be a solvent which acts as a vehicle for the binder, it may be lowerfraction oil which acts as a coating, or it may be another wettingagent. In any event, the binder must be carried away with the sawdust soa clean 'saw blade is, at all times, maintained.

A further object of my invention is to provide, in combination with abandsaw machine for splitting a thin sheet of cellulose fiber board, aspray type dispenser means which will bathe both faces of the saw bladewith a liquid and which, because of the concentric nozzle structureemployed, will do so more efficiently and effectively than thosemechanisms heretofore employed.

Yet another object of my invention is to provide a frame member having aflat area defining a datum plane, a continuous bandsaw blade whichintercepts said datum plane at right angles adjacent two spaced areas,the first such area to define a saw work plane and the second to define'a return plane, a work bed which is rotatably adjustable with respectto the bandsaw blade, and a plane work feed tunnel for the boards.

-More particularly, the work bed and plane work feed tunnel abovedefined are tilted at an angle to the datum plane and the saw workplane, respectively, so the insulating board which is fed through thetunnel will be cut at an inclined angle to produce two tapered pieceswhich are wedge-shaped.

Another object of my invention is to provide, in combination with a workbed, a plurality of work guides, fences, and power driven feed rollswhich are aligned with precision and accuracy in pairs and which arespaced one from another to bound a plane work feed tunnel of the samewidth and thickness as a board which is to be split or resawed. Thistunnel serves to steer and to guide the board in a unique manner sinceit bounds, bears upon, and engages the top, the bottom, and both facesof the board.

. The above and other objects, capabilities, and

3 being taken substantially on the line 3-3 in Fig. .2, showing thespray type dispenser jmeanswhich floods or bathes the saw blade with aliquid or solvent and showing the two part fabric wiper which is spring.biased to contact jthe faces of the saw blade and spread and in. theliquid or solvent thereover;

" [,Fig. 4 is an enlarged detail view, taken sub ;stantially on the line44 of Fig. 1, showing two "sheets. of soft insulating board being. movedlalong the feed tunnel which is defined and bounded by a plurality ofguides, rolls and Fig. 5 is a perspective view'showing a sheet of "the;insulating board with'the" saw blade in the llt'erffoneof the ressureshoes here being show-nin correct posltion'bearing against the side ofthe board (the other pressure shoe is not shown in this view); Fig. 6 isa perspective of the saw blade, lower guides, and bed with the boardremoved;

Figs. 7 and 8 are related enlarged and'somewhat diagrammaticcross-sectional views looking :-down through a kerf as it is cut'bya-co'nventional saw tooth and by a scraping type saw tooth,respectively, Fig; '1 illustrating conventional orprior art, forming nopart of applicant-s surfaced, clean kerf produced by the smooth Figs. 9,10 and 11 are related top, front and back views, respectively, showingone form of the tapered or scraper type tooth with which the method ofthe instant invention is practiced;

and

' Fig. 12 is an enlarged detail view which is more or less diagrammaticand which is taken in cross section through a sheet of insulating boardwith the saw in the kerf and with the pressure shoes bearing tightlyagainst the sides of the board so the thin edge will not crumble orbreak off.

In Fig. 1, I have shown a more or less conventional single blade bandresaw machine with which I have embodied the principles and novelelements of my invention. This machine includes a main frame member I Ihavingthe usual horizontal flat top area defining a datum plane. Thisdatum plane is so labeled in Figure 1. An electric motor I2'is mountedupon the flat topof the frame member and is joined, by a belt I3 and twopulleys M, to the lower or power saw wheel l5. This power wheel I 5 inturn, is mated to an upper or idler saw wheel l6 and a continuousbandsaw blade I! is reeved thereover. Thus, the bandsaw blade I! ispower driven to intercept the datum plane at right angles adjacent twospaced areas. The first such area'I define as a saw work "plane (see l8wherein the blade moves down) "filed November '16, 1951, Serial No.256,714, the

instant machine may be equipped with the mated inner and outer halves ofa bandsaw guide 20. Further, the work bed 2| of the resaw machinerotatably is adjustable, upon a journal bearing Zia; with respectto theaforementioned datum plane. Such rotational adjustment takes place abouta journal bearing axis which lies within the datum plane and within thesaw work plane 18, the axis being located in a direction perpendicularto the plane of the drawing of Fig. 1. In conjunction with therotational'adjustment, the work bed carries a massive ear 22 whichcooperates with a slotted slide 23 and a. bolt 24 toadjust and to setthe angle between the plane of the work bed and the datum plane.

This angle, as indicated in Fig. 1, is a small acute angle for thepurposes of the instant invention so that tapered pieces will be cutfrom a rectangular board.

In comparison of Figs. 1 and 4, the work bed 2| carries a plurality ofwork guides, fences, and power driven and idler feed rolls whichprotrudethereabove for adjustment about the or horizontal guide or fence28.

Journal hearing lla with the work bed. These elements :include fourpower driven 560(131011515,

slide having a tightening bolt 32 which is adapted to 'grip thecomplementary upstanding pipe 33. Thus, since the pipe 33 is joined tothe work :bed 2|, as by bolts 34, and since the valrious'rolls andtheside fence 2'! also are carried by the work bed 21., rotation of thelatter will cause these elements to tilt or rotate the same amount. In

summary, then, the various fences, guides, and

rolls may be said to define a plane work :feed

:tunnel :which is adjustable in sizeand which is best made to conform, a.complemcntary'manner, to the size of the board which .is-to .besawed.

The rolls and side fences grip thgtwo sides of .a

board, the top fence slidably guides the top of the board, and the workbed guides the bottom thereof. Further, because the various adjustmentsare provided,-the boundaries "ofthe tunnel canbe set to a small fractionof an inch. Such accuracy is important to my .invention.

In '4, another important feature of my invention isshown. Thus, there isshown a pair at insulating boards in the-process of being fed,

by the hands of a saw-yer, through the aforementioned feed tunnel andagainstthe vbandsaw blade 11. These boards, in accord with an importantfactor in this invention, arean insulating boardwhich, becauseof-its:soft,-spongy and weak nature, is very difficult to split. Both of'the boards are identified b the numeral 35 and, as they now through thework tunnel, the various guides and fences bear upon the top, the bottomand both faces thereof. Furthermore, as the boards actually are beingsawed by the blade 41, a pairof flat pressure vshoes 36 bear upon andsupport the outer surfaces of the board and the cut pieces with acompressive force. This compressive force is generated by an adjustablecompression-spring 31 which is held intermediate one .of the pressure.shoes and the secondary "frame member supporting the shoe. The springforce is adjusted by a threaded nut system 31a. As best shown in Figs. 4and 12, each of :the flat shoes 36 has a tapered end 36a so, in effect,.a funnel is formed. Further, the entire shoe extends upwardly to apoint closely adjacent the top of the board and it extends -.rearwardlysubtsantially the width of the saw blade. Thus, the out pieces of theboards 35 are pressed tightly together as they pass over the saw blade.By this pressing action, the-shoes 36 serve two separate functions.Firstly, they support the cut pieces to prevent crumbing and, secondly,they amplify and support the shaving and planing action of the saw teethas hereinafter will be explained with reference to Figs. .9, 10 .and 11..In use, these functions areevidencedrby a slight lateral movement ofthe nut system 3-1 aeach time a board passes between the shoes .315.Thus, the pressure shoes 36 form an important part of my invention.

Further to illustrate the structureand function of the pressure shoes36, I have provided the mlarged diagrammatic view of 12. In this figure;the arrows :F indicate :the direction in which the board 35 is fedagainst and past the saw blade H and the arrows P indicate the directionin which the pressure shoes 36 exert a force against the sides of theboard. By way of :example, -I have found that a total force (P) of about:10 pounds is sufficient to support a :of Firtex insulating board whichis one half inch thick, 16 inches high and four feet long. Thus, theboard-itself is quite p ngy and yieldable in contrast to lumber orhardboard. Consequently,

teeth of the saw blade are attempting to :rip

and to plane a material which gives, under pressure, much as a piece ofcardboard would give. I counteract this give by supporting the 'boardwiththe pressure shoes. On the other hand, the shoes 36 cannot pressinwardly at a point opposite the saw teeth or the saw will bind andoverheat. This danger points up another reason for forming the'shoes 36with the tapered, :cut-

away portion 360.. In short, the shoes must be provided to support thecut pieces rearwardly of the gullet line and along the sides of the sothe sawing can proceed, but they also must be relieved or taperedopposite the teeth so the sawing can continue.

Yet another function is served by the pressure shoes 36. Thus, as iswell known in the sawing art, thatportion of the bed of the resawmachine which is located directly below the tooth and gullet structureshown in Fig. 12 is relievedor cutaway to provide an opening (-54, Fig.-6) through which the blade and the teeth maypass. -.Consequently, amajority of that portion of the board which is shown in Fig. 12 isunsupported from beneath. However, this same portion is the-mostcritical area in the entire weak, spongy board. This is for the reasonthat the blade If! is moving down through the unsupported area and theteeth are pulling upon and ripping the kerf over this area. Withconventional methods of sawing, this pull will break off and crumble thethin lower edge of the board and imperfect pieces will result. Inpractice, a lateral support pressure is exerted against the sides of theboard. This support may be provided by the pressure shoes 36 or by anequivalent structure. In any .event, by holding the cut pieces togetheragainst the saw blade directly behind the teeth, asupport is provided tocounteract a certain amount of the tooth pull. This support, then, is inaddition to that support which resists the lateral -give.of the spongymaterialand it is an important part of my invention.

Returning now to a comparison of Fig. '1 with Figs. 2 and 3. the latterare enlarged detail views of thespray type dispenser means 38 which ismounted in the return plane 13 of the saw blade. Thus, .a longhorizontal mounting rod '39 protrudes from and is carried by anupstanding rear portion .of the main frame member ll. Four separateclamps encircle and grip this rod 33. Asshown in Fig. 2,1two of theseclamps carry the mated concentric nozzle structure 40, whereas .two morecarry the complementary halves of a fabric wiper 4|. The nozzles .40 areaimed or directed at the front .of the saw blade ll against the .gulletline of the teeth. The fabric wipers Al, on the other hand, contact theentire lateral area of the saw faces. Thus, each nozzle in-.cludesaliquid supply hose [2 and an air supply hose 43. As indicated inFig. 3, air'under pressure is emitted from the outermost or annularnozzle, whereas liquid, such as the aforementioned solvent or .oil, .isemitted from the central or circular nozzle. In effect, this provides anatomizer action which breaks up the small drops of liquid to form a finemist or spray as indicated diagrammatically at 44. Further, as shown inFig. 3, this spray 44 contacts the saw faces just below the two fabricwipers 4|. Since the wipers 4| are spring biased into contact with thesaw faces, as with a spring 45, the fabric soon becomes wet orimpregnated with the liquid and the entire lateral area of the blade iswiped, flooded or bathed with a uniform coating of the liquid. By way ofexample, if the binder in the board is a bitumen, the liquid should be asolvent which is a lighter fraction of the same source material. On theother hand, I have tried water as a wetting liquid. In any event, thewetting agent should wet or flood the sides of the blade completely so acoating is provided. If this coating isthorough and complete, the bindermaterial which is exuded from the board will not stick to the blade.Instead, the binder will be wiped off by the sawdust during the sawingoperation. Further, a certain amount of the liquid also will be wipedoff and it is for this reason that an efficient spray type dispensershould be used.

- Turning now to Figs. 9, and 11, I have shown a typical shaving orplaning tooth which is capable of producing the smooth saw resultspreviously described. This particular form of the tooth is made with arelatively flat face 46, a straight top 41, and with divergent planingedges 48. In function, the straight top edge 41 of the tooth servesinitially to rent out a narrow kerf in a board and the divergent edges48 Widen the kerf to it'seventual width by planing and dressing thewalls defining the kerf. The taper whichproduces the divergent edges mayvary from zero; to ,005 inch or more, depending upon the action desired.I v

This function of a shaving type tooth best is'illustrated in Fig.3 wherea cross section of the tooth is shown as it forms a kerf in a softcellulose fiber insulating board 49. Thus, the narrow straight top 41 ofthe face 46 is routing out the floor of a kerf through the board and thedivergent edges 48 are planing, shaving, and dressing the walls definingthe kerf. In Fig. '7, on the other hand, a conventional saw tooth 50isforming a kerf in a similar soft fiber board 49. In this latterfigure, the tooth edges 5| are ripping and tearing out the fibers.Because the conventional tooth 50 has no shaving, or planing action, thesides of the kerf are not smooth as in Fig. 3, Instead, the edges 5| aretearing, gouging and ripping without smoothing. Fig. '7 is diagrammaticand is enlarged considerably to show the rough saw kerf as it wouldappear under a microscope. Thus, according to studies I have made, theconventional saw tooth actually loosens and detaches the cellulosefibers and. splinters from a thin layer underlying the surfaceof thekerf. This pulling and tearing of the fibers makes rupture lines 52which, when the saw approaches the thin edge of a cut, break off andactually cause the edges of the board to fracture, crack and give way.As shown in Fig. 8, on the other hand, the planing action of thedivergent edges 48 on the smooth sawing tooth, shaves and dresses thesurfaces of the kerf and minimizes the rupture lines 52. Further, theplaning action of the edges 48 serves to shave off rather than to tearand pull the minute fibers or splinters which are present in the softboard 49'. The overall kerf width, however, is the same in both Figs. '7and 3 since the effective tooth widths are identical.

Turning now to Fig. 5, I have shown a soft cellulose fiber insulatingboard 35 in the process of being resawed or split edgewise and at ataper by the saw blade Because the aforementioned datum plane and thesaw work plane l8 are perpendicular, one to another, whereas the workbed plane and the plane of the work feed tunnel and the board also areperpendicular, one to another, the angle 53 of Fig. 5 is equal to theacute angle which is shown in Fig. 1 between the datum plane and workbed plane. This small acute angle produces the desired taper in theboard 35 as it is split and the structure bottoming the same is animportant part of my invention. Fig. 6 likewise has been enlargedsomewhat and the board has been removed to reveal the opening 54 throughwhich the saw blade I! passes as it travels down below the flat shoes36. This opening is bounded by a fork which is an extensionof the workbed 2| and by the two lower guides 51 which are conventional in a resawmachine. Thus, Fig. 6 serves to illustrate one of the importantdifferences between my invention and practices in attempting to split orresaw an insulating board. For example, Fig. 7 illustrates how theconventional saw tooth breaks off and tears out rather large pieces andchunks ofthe board 55; These pieces and chunks pile up and accumulate inthe opening 54 and soon cause the saw blade I! to run hard. After aperiod of time, enough friction is created adjacent the clogged opening54 to cause the material from the board to burst into flame. vThe dangerof fire is even more enhanced if the binder material is flammable. Withthe tooth of Fig. 8,the pressure shoes 36, and the spray typedispenserpreviously mentioned, however, the sawdust parti: cles 56 aresomewhat thinner and fiakier than those created with the conventionalsaw tooth. Further, since the board is not brokenor chipped in the kerfand along the thin edges, no large diameter chunks are produced to clogthe opening 54. Additionally, the flaky shaving particles 56 are coatedwith the liquid which has been carried onthe blade I1 and whichoriginated with the spray type dispenser 38. Thus, with my machine, theopening 54 does not clog up, no fire hazard is presented, and thatbinder which is released from'the board immediately is wiped away by thesawdust.

, In use, the bandsaw machine of Fig. l is started up and the spray typedispenser 38 is turned on. Thereafter, the insulating boards 35 are fedto the rectangular feed tunnel which is defined by the power driven feedrolls 25, the side fences 21, the horizontal top guide 28, and theworkbed 2|. As a board is moved against the saw blade H, the flatpressure shoes 36 grip the side faces thereof, compress the board, andhold the cut pieces against the sides of the saw blade, firstly, to helpproduce the desired shaving'and planing action with the divergent edges48, and, secondly, to keep the thin edges of the board from crumbling.Further, if the boards 35 are made with a binder such as a low meltingpoint bituminous binder, the heat of the sawing action tends to causethe binder to exude.

However, because the spray type dispenser 38 has coated the saw faceswith a liquid, little, if any, of the binder will stick to either theblade or the teeth. Instead, the liquid and the sawdust will actasvehicles or carriers to scrape away 1 1 and wipe ofi the-binder. asisillustrated diagram.- mati'celly in Fig: 8.

In summary, my invention: relates. toinsulatin boardv of the type:-which. is formed. inthin rec.- tangular sheets=of more. orrlessuniformthickness front a fibrous material and abitumen. or. other binder.Because of the factors heretofore explained; this method. is ofoutstanding. usefulness when the-thickness of the-board: doesnot. exceedone half inch. Inthis latter case..the tensile and cohesive-strength ofthe board is-so. limitedthat conventional methods and machines. cannotsplit. theboard withoutcracking off large pieces and. without starting:a. fire. With. my improved machine; howeven. these boardamay be resawedor split edgewise; with no. cracking or danger. of fire. Further, the.plane. of the,- sawkerf will be relatedto the planes ofthe rectangularsizesof theboard andit wilLbe inclined. at a. smallacute angle thereto.(see Fig. 5) taproducetwo. tapered two tapered pieceshaving. a butt.approximately three-eighths. inch thick. and. a shank end. approximately0ne-.-eig-hth.inch. thick. The, length and widthot thetapered; piece,.of course, areunaffected. Given. such. a. board; my method. in.-

cludes. the provision of a1 continuous saw. blade having. teeth.withdivergent edges. Further... a. plurality: of fence. and guide meansareprovided onthe. feed. side of.- theblade and beside the blade. forholding. and. guidingv the top,. bottom,-. and sides of. eachsheet-asit; appmachestheblade and the-bottom andsides .as.the board.actually, isbeing. sawed. Further. the sideaarepressed and held.together. as, theypass. over. the saw blade.- Still. further,. aconstant. velocity feedmechanism is providedto. feedeachboard pastthefence and guidemeans. and to thesaw. blade. To produce the. taperedpieces. the feed-.mechanism-v and the. fence and. guide means. are.inclined at an. acute angle. or tilt. to. the. saw blade. as. previouslyexplained. Sequentially,,the stepsof'my invention include coating orwetting both surfaces of the saw blade with a liquid so that binderwhich is caused. to exude by the heat of. the sawing actionwillbe wipedaway by the sawdust. Contlnuing, a plurality of therect'angul'ar boardsare fed; edgewise; one after the other, to the feed mechanism and sawblade in a constant stream and at a constant velocity with theend ofeach board in abutment with the following boardi finally, the-cuttapered pieces are heldtogether with a light compressive: pressure untilthe are well past. the: gullet' line: of. the; saw' teeth so. theplanningaction of teeth: is enhanced and splitting; crumbling andcracking are; prevented;

Withthebandsaw machineeof. myinvention, on

These. areas guides... fences andpower driven feed. rolls; I! mountedupon the work bed and: are aligned inspaced pairs to bound, inoutlineapl'ane'vmm feed tunnel of thesame height and thickneoaz-fl theboards which are.- to; be sawed. The. work feed. tunnel is inclined atan angle tothe. datum. plane. and-to theplane of thesaw Furthen,,thotunnel. terminates adjacent, the novel pressure shoes. Finally, thebandsawmachine isprovided. with a. dispensermeans. which sprays an!spreads-aliquidover both faces of: the saw; bladl as the latter passesthrough the return planm cumulatively, these improvements provider amachine with. which insulatingfboardcan hare.- sawed or splitedgewisewithout, chipping, cracking, crumblingor. catching on fire.

I- claim:

1.. A bandsaw. machine for splitting a thinxshoot ofsoftcellulose fiberboard-into two tapered pieoem whichmromore thin than but.of. the samelength and width; as the original-- board; said; machinv. comprising, aframe member operatively cam!- ing a power. drivenbandsa-w blade having;herb formingv and kerf planing teeth and; having; a horizontal fiatsurface,- defining adatum' plane; a work bed adjustably mounted uponsaid tram: andhavinga fiat area defining aworkplanegsaid work. plane anddatum planebeing; inclined at. am acuteangle .to one another; a. pairofspringqbl'aooda and parallel mounted flatshoos positioned; one: oneachside of said. saw bladeto-hold the-mm pieces of boardtogether asthey passoverp'the blade, and. a spray type dispenser means; carried bysaid frame adjacent said blade for; bathing: both facesof the latterwith liquid.

2'. A- bandsaw maohinefonj azthim sheet of soft cellulose fiber boardinto two: tapered pieces-which are more thin thangbut'zof the somelength and width as;.the-original-.board;,said'.ma' chine comprising: aframe member operativelr carrying a power drivenbandsaw blade havingker-fi forming and kerf planing; teeth: and'havingr a. horizontal. fiatsurfacedefining a; datum plane, a. work bed adjustablymounted: upon;said frame and'having a fiat'areadefining awork-plane.. said! workplane. and. datum plane being inclined atan acuteangletoone another-,apair of. springbiased. andparallel mounted flat shoespositioneds one on:eachside of said-save blade to-hold the-cutpicces: of board. togetheras. they; pass; oven the. blade, the. areas of. said.fiatshoesalignedwith: the: kerf formingand kerf planing; teeth;tapering". away from theremainder oi the; opposed faces of? said. flat.shoes. to. inhibit localized; pressure generated. at. the. cutting andplaning. ImB'Of. said. teeth-..

3.v Abandsaw machine for splitting athin'sheet. of" soft cellulose,fiber. board, into two tapered. pieces which are more thin. than, but.of 'thesame. length and width as. the. original board. said machinecomprising: aframemember. operatively C r i g. a. power driven. bandsawblade, having kerf forming. and. kerf. planing teeth and having. ahorizontal flat surfacedefining a datumplane. a workbed. adj ustabLv.mounted. upon said frameandhaving a flat-area defining, a workplane,said: work plane and datum plane being, inclinedat anacute angle to oneanother, a. pair of spring biased and parallel mounted fiat shoespositioned. one: on. each side of said saw blade? to-held. the cut.pieces. ofboard together as; they pass over: the blade.

R. FERRARI.

(References oni'ollowing page References Cited in the file of thispatent Number UNITED STATES PATENTS Name Date Aylesbury Oct. 10, 1882Van Severen Dec. 22, 1891 Thom Sept. 6, 1892 Pake Apr. 18, 1893McWilliams Mar. 9, 1909 Hunt Aug. 7, 1923 Shaw Mar. 22. 1932 NumberNumber 10 17,137

Name Date Burton Aug. 9, 1932 Hutchings May 22, 1934 Hutchings Oct. 9,1934 Ferrari et a1 Feb. 23, 1937 Litty Dec. 15, 1942 FOREIGN PATENTSCountry Date Great Britain Sept. 13, 1895

